Ultraviolet/infrared absorbent low transmittance glass

ABSTRACT

An ultraviolet/infrared absorbent low transmittance glass is formed of base glass containing 65 to 80 wt. % SiO 2 ; 0 to 5 wt. % Al 2 O 3 ; greater than 2.1 to less than or equal to 10 wt. % MgO; 5 to 15 wt. % CaO wherein a total amount of MgO and CaO is 7 to 15 wt. %; 10 to 18 wt. % Na 2 O; 0 to 5 wt. % K 2 O wherein a total amount of Na 2 O and K 2 O is 10 to 20 wt. %; and 0 to 5 wt. % B 2 O 3 , and colorants including 1.25 to 2.2 wt. % total iron oxide (T-Fe 2 O 3 ) expressed as Fe 2 O 3 ; 0.001 to 0.018 wt. % CoO; 0 to 0.0004 wt. % Se; and 0.028 to 0.2 wt. % NiO, wherein the glass has a turquoise blue or deep green color.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This is a continuation-in-part application of a patentapplication Ser. No. 10/131,237 filed on Apr. 25, 2002, which is acontinuation-in-part application Ser. No. 09/524,589 filed on Mar. 14,2000, now U.S. Pat. No. 6,395,660, which is a continuation-in-partapplication Ser. No. 09/189,638 filed on Nov. 10, 1998, now abandoned,which is a continuation-in-part application Ser. No. 08/909,728 filed onAug. 12, 1997, now abandoned.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

[0002] The present invention relates to an ultraviolet/infraredabsorbent low transmittance glass. More particularly, it relates to anultraviolet/infrared absorbent low transmittance glass which has analmost neutral color such as turquoise blue shade and deep green shadeso that it is useful for windows of vehicles or buildings when used incombination with a glass having green shade with high visible lighttransmittance, and which has low or middle visible light transmittance,low total solar energy transmittance, and low ultraviolet transmittanceso that it is suitable for use as privacy glazing in a vehicle.

[0003] Recently, a variety of glasses with ultraviolet/infraredabsorbability to be used as a vehicle windshield have been proposed withthe view of preventing degradation of luxurious interior materials andreducing cooling load of the vehicle. In view of privacy protection,glass with relatively low visible light transmittance is preferably usedfor a rear window glass of a vehicle. Such kinds of glass include thefollowings.

[0004] For example, a dark gray colored infrared absorbent glassdisclosed in Japanese Patent Publication No. 7-29813 consists ofsoda-lime-silica glass including colorants consisting of 1.00 to 1.7weight percent. Fe₂O₃ (total iron), at least 0.27 weight percent FeO,0.002 to 0.005 weight percent Se, and 0.01 to 0.02 weight percent CoO.The glass exhibits luminous transmittance less than 32 percent and totalsolar infrared transmittance less than 15 percent at 3.9 mm thickness.

[0005] A dark gray colored glass disclosed in Japanese UnexaminedPublished Patent Application No. 8-157232 consists of soda-lime-silicaglass including colorants consisting of 0.8 to 1.4 weight percent Fe₂O₃(total iron), less than 0.21 weight percent FeO, 0.05 to 1.0 weightpercent TiO₂, 0.02 to 0.05 weight percent CoO, and 0.0005 to 0.015weight percent Se.

[0006] A neutral gray colored glass disclosed in claim 25 of U.S. Pat.No. 5,393,593 has a base glass composition comprising 66 to 75 weightpercent SiO₂, 10 to 20 weight percent Na₂O, 5 to 15 weight percent CaO,0 to 5 weight percent MgO, 0 to 5 weight percent Al₂O₃, and 0 to 5weight percent K₂O, and colorants consisting of 1.00 to 2.2 weightpercent Fe₂O₃ (total iron), at least 0.20 weight percent FeO, 0.0005 to0.005 weight percent Se, and 0.010 to 0.030 weight percent CoO. Theglass exhibits luminous transmittance less than 35 percent and totalsolar infrared transmittance less than 20 percent at 3.9 mm thickness.

[0007] A soda-lime-silica glass disclosed in Japanese Publication of PCTNo. 8-506314 has a neutral color by including primary iron given by thefollowing expression:

FeO (weight percent)≧0.007+(optical concentration−0.036)/2.3

[0008] and 0.25 to 1.75 weight percent Fe₂O₃ and at least one selectedfrom a group consisting of Se, Co₃O₄, Nd₂O₃, NiO, MnO, V₂O₅, CeO₂, TiO₂,CuO, and SnO. The glass exhibits luminous transmittance more than 32percent, ultraviolet transmittance less than 25 percent, direct solarenergy transmittance at least 7 percent less than the luminoustransmittance, and dominant wavelengths preferably less than 570nanometers at 4 mm thickness. Certain embodiments thereof may be used asa privacy glazing.

[0009] In both the dark gray colored infrared absorbent glass disclosedin Japanese Patent Publication No. 7-29813 and the dark gray coloredglass disclosed in Japanese Unexamined Published Patent Application No.8-157232, a great quantity of Se is used for providing a desirablecolor. Such a great quantity of Se is unpreferable for the environmentbecause Se has toxicity and is easy to vaporize. The above dark grayglass including 0.05 to 1.0 weight percent TiO₂ as an essentialcomponent is unpreferable because TiO₂ is expensive to increase thebatch cost.

[0010] The neutral gray colored glass disclosed in U.S. Pat. No.5,393,593 is also unpreferable because of the great content of Se. Thegreat content of FeO is preferable in view of heat ray absorptivity, FeOis on the contrary not preferable because it selectively absorbsinfrared ray in a wavelength from 1,000 to 1,200 nanometers so that incase the glass is produced by a normal melting furnace, it absorbs mostefficient portion in flame luminance distribution so as to lower thetemperature of bottom base of the furnace and then contribute to variousdefects.

[0011] Though the aforementioned glass with low visible lighttransmittance is superior in view of privacy protection, an occupant ina vehicle cabin sees outside quite unclearly through the glass. On theother hand, a glass with middle transmittance can be sufficient to someextent for both privacy protection and safety. These types of glass arechosen according to portions in a vehicle and circumferences.

[0012] The aforementioned glass includes selenium in high concentrationto provide optical properties, without essentially including nickel.

[0013] The glass of Japanese Publication PCT No. 8-506314, which can beused for privacy protection, is provided with a neutral color byincluding colorants consisting all of nickel, selenium, and cobalt, justas described in this specification. However, it is necessary to add agreat quantity of Se since the content of nickel is low.

OBJECT AND SUMMARY OF THE INVENTION

[0014] It is an object of the present invention to provide anultraviolet/infrared absorbent low transmittance glass which has analmost neutral color such as turquoise blue and deep green and which haslow or middle visible light transmittance, low ultraviolettransmittance, and low total solar energy transmittance.

[0015] The ultraviolet/infrared absorbent low transmittance glass of thepresent invention consists of a base glass, that is, the majorconstituents comprising:

[0016] 65 to 80 wt. % SiO₂;

[0017] 0 to 5 wt. % Al₂O₃;

[0018] greater than 2 to less than or equal to 10 wt. % MgO;

[0019] 5 to 15 wt. % CaO wherein a total amount of MgO and CaO is 7 to15 wt. %;

[0020] 10 to 18 wt. % Na₂O;

[0021] 0 to 5 wt. % K₂O wherein a total amount of Na₂O and K₂O is 10 to20 wt. %;

[0022] 0 to 5 wt. % B₂O₃,

[0023] and colorants comprising:

[0024] 1.25 to 2.2 wt. % total iron oxide (T-Fe₂O₃) expressed as Fe₂O₃;

[0025] 0.001 to 0.018 wt. % CoO;

[0026] 0 to 0.0008 wt. % Se; and

[0027] 0.028 to 0.2 wt. % NiO.

BRIEF DESCRIPTION OF THE DRAWING

[0028]FIG. 1 is a diagram showing changes in color shade duringreinforcing process in each example.

PREFERRED EMBODIMENTS

[0029] The description will be made as regard to an ultraviolet/infraredabsorbent low transmittance glass composition. It should be noted thatcomponents will be represented with percentage by weight.

[0030] SiO₂ (silica) is a principal component for forming skeleton ofglass. Less than 65% SiO₂ lowers the durability of the glass and morethan 80% SiO₂ raises the melting temperature of the glass so high.

[0031] Al₂O₃ is a component for improving the durability of the glass.More than 5% Al₂O₃ raises the melting temperature of the glass so high.The preferable range of Al₂O₃ is between 0.1% and 2%.

[0032] MgO and CaO improve the durability of the glass and adjust adevitrification temperature and viscosity of the glass during molding.More than 10% MgO raises the devitrification temperature. Less than 5%or more than 15% CaO raises the devitrification temperature of theglass. The durability of the glass is lowered when the total amount ofMgO and CaO is less than 7%, while the devitrification temperature isincreased when the total exceeds 15%.

[0033] Na₂O and K₂O prompt the glass to melt. The efficiency ofpromotion of melting becomes poor when Na₂O is less than 10% or thetotal of Na₂O and K₂O is less than 10%, while the durability of theglass is lowered when Na₂O exceeds 18% or the total of Na₂O and K₂Oexceeds 20%. K₂O is preferable not to exceed 5% because of its expensivecost.

[0034] B₂O₃ is a component for improving the durability of the glass,prompting to melt, and yet enhancing the ultraviolet absorption. B₂O₃should be less than 5%, since the transmittance is reduced also at avisible range so that the color of the glass is easy to tint yellow anddifficulties during molding are caused due to the vaporization of B₂O₃when B₂O₃ exceeds 5%.

[0035] Iron oxide is present in the form of Fe₂O₃ and the form of FeO inthe glass. Fe₂O₃ is a component for improving the ultravioletabsorptivity and FeO is a component for improving the heat rayabsorptivity.

[0036] When the total amount of iron oxide expressed as Fe₂O₃ (T-Fe₂O₃)is less than 1.2%, the efficiency of ultraviolet and infraredabsorptivity becomes small so as not to provide desired opticalproperties. On the other hand, when T-Fe₂O₃ exceeds 2.2%, there is anunpreferable possibility that the temperature around a crown of a glassmelting furnace exceeds its refractory temperature due to absorption ofthe heat ray by the ferrous oxide. In addition, in case of successivelyproducing glass by a glass melting furnace with T-Fe₂O₃ exceeding 2.2%,long time is required to alter a glass composition in the furnace.T-Fe₂O₃ content is preferably equal to or more than 1.2% and less than1.8% (more preferably between 1.25% and 1.35%) or between 1.8% and 2.2%.

[0037] Equal to or more than 1.2 and less than 1.8% T-Fe₂O₃ can offeradvantages of small load to the furnace because the glass composition inthe successive glass melting furnace is altered to another compositionwithin a short time. In this case, sufficient efficiency of ultravioletabsorptivity is sometimes not obtained only by iron. However, theefficiency of ultraviolet absorptivity can be improved by adding, forexample, CeO₂, TiO₂ within the range defined by the present invention.

[0038] Particularly 1.25% to 1.35% T-Fe₂O₃ can offer the aforementionedadvantages and sufficient efficiency of ultraviolet absorptivity only byiron.

[0039] 1.8% to 2.2% T-Fe₂O₃ makes the time longer to change the glasscomposition in the furnace, and the load to the furnace becomes greaterHowever, great efficiency of ultraviolet absorptivity can be obtainedwith low batch cost.

[0040] Fe₂O₃ has a function of particularly increasing the absorptivityin ultraviolet range when glass is reinforced by air blast cooling. Thismeans that the glass of this invention can obtain enough efficiency ofultraviolet absorptivity without using expensive ultraviolet absorbentsuch as CeO₂ and TiO₂. When T-Fe₂O₃ is in the range mentioned above, thedesired color shade of the glass can be obtained after discoloration dueto the reinforcement process by air blast cooing.

[0041] The ratio (by weight) of FeO/T-Fe₂O₃ is preferably between 10%and 40%. When the ratio is less than 10%, enough heat ray absorptivitycan not be obtained because of a small amount of FeO.

[0042] When the FeO/T-Fe₂O₃ ratio exceeds 40%, the visible lighttransmittance is reduced and the color is of a blue tint. In addition,nickel sulfide particles are sometimes present in the molten glassbecause of a great quantity of Fe²⁺ having reducing characteristics inthe molten glass. The FeO/T-Fe₂O₃ ratio exceeding 40% causes streakswith enough silica and causes silica scum. The FeO/T-Fe₂O₃ ratio in arange between 10% and 40% brings a green shade which is an almostneutral color having high ultraviolet absorbability and high heat rayabsorptivity. In this case, values converted to Fe₂O₃ are used for thecontent of FeO.

[0043] CoO is a component for forming an almost neutral color such asturquoise blue shade and deep green shade by cooperating with Se and/orNiO, and Fe₂O₃ for controlling the visible light transmittance. Lessthan 0.001% CoO can not form a desired color shade and makes the visiblelight transmittance too high. More than 0.03% CoO makes the color of tooblue tint and reduces the visible light transmittance. Equal to or lessthan 0.018% (180 ppm) of CoO makes the color shade of the glass darkgreen.

[0044] Se contributes a pink color, so that it reduces the excitationpurity with the aid of a complementary color of CoO. When NiO isincluded, Se may not be always included. More than 0.0008% Se reducesthe visible light transmittance. When using Se, the content thereof ispreferably in a range of equal to or less than 0.0008% (8 ppm), morepreferably equal to or less than 4 ppm, yet more preferably equal to orless than 2 ppm, most preferably equal to or less than 1 ppm. The moredeep color the glass has, the lower its visible light transmittancebecomes and the glass generally has the high excitation purity and thestrong color impression even in the same color co-ordinate. Se of lessthan 0.0008% (8 ppm) in the glass decreases the excitation purity of theglass and makes the glass to have a soft color at the same color tonewithout losing the objective green or blue shade green color of theglass. As mentioned, the desired color shade can be obtained with asignificantly smaller amount of Se than the amount conventionallyrequired or without Se.

[0045] NiO is a component for controlling the visible lighttransmittance and for reducing the excitation purity as CoO. When NiO ismore than 0.2%, nickel sulfide stones are sometimes present in theproduct and the visible light transmittance is reduced. In addition, theobtained shade becomes too greenish. The content of NiO is in a rangebetween equal to or more than 0.028% and less than 0.2% preferably in arange between 0.05% and 0.2% for low visible light transmittance.

[0046] When the concentration of NiO in the glass is too high, there isa possibility that NiO coagulates to form a nickel sulfide stones.However, when NiO is in the range defined by this invention, the desiredcolor shade can be obtained without producing the nickel sulfide stones.

[0047] It is known that the coordination number of NiO varies accordingto the rate of cooling glass so that the colore of the glass varies.This is because the cooling varies the coordination number of oxidearound Ni²⁺ from 6 into 4 and thus varies the optical absorption. Theabsorption of Ni²⁺ with 6 coordinating atoms exists around 430nanometers so as to contribute yellow to the glass, while the absorptionof Ni²⁺ with 4 coordinating atoms exists from 500 to 640 nanometers.Therefore, the excitation purity would be reduced to obtain thepreferable shade by using Ni²⁺ with 4 coordinating atoms. Windshields ofa passenger car are normally reinforced by air blast cooling for safety.The reinforcement process by air blast cooling also varies the coloringcondition of NiO. In the present invention, the desired color shade canbe obtained without adding Se by the discoloration due to thereinforcement process by air blast cooling.

[0048] CeO₂ is a component for improving the ultraviolet absorptivityand is present in the form of Ce³⁺ or in the form of Ce⁴⁺ in glass.Particularly, Ce³⁺ is effective in absorbing ultraviolet with lessabsorptivity in the visible range. In the present invention, oxide ofCe³⁺ is also expressed in terms of CeO₂ and is included in the totalamount of CeO₂.

[0049] TiO₂ is a component for improving the ultraviolet absorptivityparticularly by interaction with FeO. TiO₂ can be added to improve theultraviolet absorptivity within such a range as not to lose the almostneutral color such as turquoise blue shade and deep green shade, or toadd a yellow tint in order to obtain the desired color shade. The use ofexpensive CeO₂, TiO₂ increases the cost so that it is not preferable touse more than 2% CeO₂, TiO₂.

[0050] One or more than two among MnO, Y₂O₅, MoO₃, CuO, Cr₂O₃, and thelike may be added as colorant and SnO₂ within a rang from 0% to 1% intotal may be added as a reducing agent in such a range as not to losemiddle transmittance and the almost neutral color such as turquoise blueshade and deep green shade. To further securely prevent the formation ofnickel sulfide stones, ZnO may be added in a range from 0 to 1%.

[0051] In the present invention, when measured by using C.I.E. standardilluminant “A”, the total solar energy transmittance (TG) is preferablylower than the visible light transmittance (YA). It is preferable thatYA is in a range from 23 to 50% and TG is in a range from 7 to 35% whenthe measurement is made based on a glass thickness of 4 mm. Morepreferably, YA is in a range from 25 to 40% and TG is in a range from 20to 35%. In case of using L* a* b* color system, the chromaticity,expressed by a* and b*, of the glass color are preferably in ranges of−9<a*<−6 and −3<b*<3, respectively.

[0052] In the present invention, the glass preferably has YA between 10%and 25% and TG between 10% and 35% at a thickness from 3.1 to 5 mm. Inthis case, the chromaticity, expressed by a* and b* under L* a* b* colorsystem of the glass color is preferably in ranges of −7<a*<−2 and−3<b*<7, respectively.

[0053] When measured by using C.I.E. standard illuminant “C” over thewavelength range 380 to 770 nanometers, the glass of the presentinvention preferably has optical properties with dominant wavelengths inthe range of 480 to 580 and excitation purity less than 11%.

[0054] The glass of the present invention preferably exhibitsultraviolet transmittance, defined by ISO 9050, less than 6%.

EXAMPLES

[0055] Hereinafter, the mode of carrying out the present invention willbe described referring to some examples.

Examples 1 through 42

[0056] Glass raw material is prepared by adding at least one of a groupconsisting of ferric oxide, titanium oxide, cerium oxide, cobalt oxide,metallic selenium, and nickel oxide into a standard soda-lime-silicaglass batch composition, also adding carbonaceous reducing agent(concretely, coke powder etc.) at a ratio of about 0.01 parts by weightper 100 parts of the glass raw material therein, and mixing them. Theglass raw material thus prepared is heated and melted in an electricfurnace at 1500° C. for 4 hours. The molten glass is flowed onto astainless plate and annealed to the room temperature as long as 16 hoursto obtain a 6 mm thick glass plate. The glass plate is then polished insuch a manner that the thickness reduces to 4 mm to become a sample.Each sample is measured in the visible light transmittance by the C.I.E.illuminant A(YA), the total solar energy transmittance (TG), theultraviolet transmittance by ISO 9050(TUV), the dominant wavelength bythe illuminant C(DW), and the excitation purity (Pe). Before measuringthe optical properties, some of the samples are cooled by blasting airafter reheating in order to reinforce them.

[0057] Tables 1-4 show base glass compositions of the obtained samples,T-Fe₂O₃ concentration, FeO (converted to Fe₂O₃)/T-Fe₂O₈ rate, CoOconcentration, Se concentration, NiO concentration, CeO₂ concentration,and TiO₂ concentration. The numerals in Tables are indicated as apercentage of the weight except that CoO concentration, Seconcentration, and NiO concentration are expressed in ppm. Thepercentages of SiO₂ are indicated without figures after decimal pointsbecause the figures after decimal points are rounded off. Tables 1-4also show the optical properties of the respective samples.

[0058] All of the samples of Examples 1 through 21 are characterized byvisible light transmittance (YA) between 23% and 50%, total solar energytransmittance (TG) between 7% and 30%, and ultraviolet transmittance(TUV) less than 6%. These are also characterized by dominant wavelength(DV) measured by using the illuminant C between 480 and 525 nanometers,and excitation purity less than 11%.

[0059] It is shown that Examples 2-6, 10, and 11 have the same orimproved properties as the glass of Example 1, although these are freeof NiO.

[0060] The examples 7-9, 12-16 have the same or improved properties asthe glass of Example 1, although these are free of Se.

[0061] In Examples 2-9, the furnace's load during melting can be reducedbecause of small amount of T-Fe₂O₃.

[0062] Examples 10-16 have improved ultraviolet absorptivity andimproved infrared absorptivity because of large amount of T-Fe₂O₃.

[0063] In order to enhance the ultraviolet absorptivity, relativelylarge amount of TiO₂ is added in Examples 17-19, and CeO₂ is added inExample 20. These examples have large ultraviolet absorptivity withoutlosing the visible light transmittance and total solar ultraviolettransmittance.

[0064] Example 21 is added with CuO in order to reduce the total solarultraviolet transmittance, and can exhibit high infrared absorptivitywithout losing the visible light transmittance and the ultravioletabsorptivity.

[0065] Examples 6, 7, and 14 have high visible light transmittance whilehaving high infrared absorptivity and yet have high ultravioletabsorptivity so that these are superior in prevention of degradation ofinterior materials and reduction of cooling load of the vehicle.Therefore, these are suitable for the privacy protection type of visiblelight transmission glass, for example, rear windows of vehicles, windowsof buildings, and the like.

[0066] The ultraviolet absorptivity and the infrared absorptivity ofExamples 22-29 are slightly small. These samples contain smaller amountof T-Fe₂O₃ and the FeO/T-Fe₂O₃ ratio is set relatively low, so that theyare superior in productivity.

[0067] Among these examples, Examples 23-29 have the same or improvedproperties as the glass of other examples, although these are free ofSe.

[0068] Example 25 exhibits middle visible light transmittance and lowinfrared/ultraviolet transmittance.

[0069] Examples 26, 28, and 29 exhibit low visible light transmittanceand low infrared/ultraviolet transmittance.

[0070] Examples 30-35 and 38 show results of measuring opticalproperties before and after the reinforcement process by air blastcooling.

[0071] Among these examples, Examples 30-32 exhibit middle visible lighttransmittance and low infrared/ultraviolet transmittance and have analmost neutral color such as turquoise blue shade and deep green shade.The ultraviolet transmittance is improved about 1.5% by thereinforcement process.

[0072] Examples 33-35 exhibit low visible light transmittance and lowinfrared/ultraviolet transmittance. The ultraviolet transmittance isimproved about 2% by the reinforcement process.

[0073] Each of Examples 30-35 has a preferable color shade which is analmost neutral color of gray tint through the reinforcement process.FIG. 1 shows a coordinate diagram of colors indicated by a*, b* forillustrating how points are moved by the reinforcement process in theaforementioned examples.

[0074] It would be apparent from the diagram that all of the points movetoward the origin according to the reinforcement process so that thecolors become closer to the desired color shade, i.e. almost neutralcolors having reduced excitation purity.

[0075] Therefore, when the glass compositions of the examples mentionedabove are used for windshields of vehicles and windows of building, goodeffects of preventing degradation of interior materials and of privacyprotecting can be expected.

Comparative Examples 1-4

[0076] Table 5 shows glass components and optical properties ofComparative Examples which are made in the same manner as Examples 1-35but the glass components are different.

[0077] All of Comparative Examples 1-4 have components out of the rangeof the present invention. Comparative Example 1 contains NiO as acolorant, an amount of which is out of the claimed range, andComparative Example 2 contains T-Fe₂O₃, an amount of which is out of theclaimed range. Comparative Example 3 has the same components as theexample of Japanese Unexamined Published Patent Application No.H8-157232 as referred above and Comparative Example 4 has the samecomponents as the example of U.S. Pat. No. 5,393,593 as referred above.It should be noted that the optical properties of Comparative Example 3are indicated in values converted based on a glass thickness of 5 mm andthe optical properties of Comparative Example 4 are indicated in valuesconverted based on a glass thickness of 3.9 mm.

[0078] It would be apparent from Table 5 that as compared with theexamples of the present invention, Comparative Examples 1 and 2 do nothave an almost neutral color such as turquoise blue shade and deep greenshade and yet do not exhibit low or middle visible light transmittance,low infrared transmittance, and low ultraviolet transmittance.Comparative Examples 3 and 4 are not preferable in view of productivityand environment because a large amount of expensive and poisonous Se isused therein.

Examples 36, 37, Comparative Example 5

[0079] Table 6 shows glass components and optical properties of Examples36, 37 and Comparative Example 5 which are made in the same manner asExamples 1-35 except the glass components are different.

[0080] As shown in Table 6, Se in the glass with a very small amountdecreases remarkably an excitation purity of the glass, while changingscarecely a color tone of the glass. More than 2 ppm of Se in the glasschanges the color tone of the glass remarkably from green to green shadebrown or green shade gray.

[0081] As detailed above, according to the present invention, anultraviolet/infrared absorbent low transmittance glass, which exhibitslow or middle visible light transmittance, low total solar energytransmittance, and low ultraviolet transmittance and which has an almostneutral color such as turquoise and deep green, can be provided.

[0082] The ultraviolet/infrared absorbent low transmittance glass havingthe almost neutral color such as turquoise and deep green can exhibitthe effect of preventing degradation and discoloration of interiormaterials and the privacy protecting effect when the glass is used for arear window glass of a vehicle, a window of a building, or the like.

[0083] The specification refers to the disclosure of application Ser.No. 909,728 filed on Aug. 12, 1997 abandoned, Ser. No. 189,638 filed onNov. 10, 1998, abandoned, and Ser. No. 09/524,589 filed on Mar. 14,2000. TABLE 1 Example 1 2 3 4 5 6 7 8 9 11 12 SiO₂ 71 71 71 71 71 71 7171 71 71 71 Al₂O₃ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 MgO 3.63.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 CaO 7.7 7.7 7.7 8.4 7.7 7.7 7.77.7 7.7 7.7 7.7 Na₂O 13.7 13.7 13.7 13.1 13.7 13.7 13.7 13.7 13.7 13.713.7 K₂O 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 B₂O₃ — 0.2 — — — —— — — — — T-Fe₂O₃ 1.9 1.3 1.7 1.5 1.4 1.4 1.7 1.5 1.4 1.9 1.8FeO/T-Fe₂O₃ 0.24 0.28 0.24 0.24 0.25 0.27 0.26 0.24 0.26 0.20 0.23 CeO₂— — — — — — — — — — — TiO₂ 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.030.03 0.03 Se(ppm) 3 5 2 3 4 3 — — — 3 1 CoO(ppm) 100 95 113 107 101 9294 96 98 125 119 NiO(ppm) 30 — — — — — 150 200 250 — — YA 30.8 38.2 34.135.1 37.0 36.2 35.4 38.2 37.5 33.1 32.9 TG 18.7 23.5 20.6 21.7 23.3 20.019.7 23.4 23.3 20.6 19.5 Tuv(ISO) 1.9 5.7 2.8 3.4 4.4 5.1 3.0 4.6 5.51.7 2.1 dominant 519 492 494 496 495 498 499 498 497 499 495 wavelengthDw excitation purity Pe 4.5 7.4 7.7 5.9 6.0 7.1 6.8 6.7 6.8 6.2 8.2

[0084] TABLE 2 Example 12 13 14 15 16 17 18 19 20 21 SiO₂ 70 70 70 70 7071 71 69 70 71 Al₂O₃ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 MgO 3.6 3.63.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 CaO 7.7 8.4 8.4 8.4 8.4 8.4 8.4 7.7 8.47.7 Na₂O 13.7 13.1 13.1 13.1 13.1 13.1 13.1 13.7 13.1 13.7 K₂O 0.9 0.90.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 B₂O₃ — — — — 0.6 — — — — — T-Fe₂O₃ 2.22.2 1.9 1.8 1.3 1.3 1.5 1.4 1.3 1.3 FeO/T-Fe₂O₃ 0.34 0.30 0.24 0.22 0.310.28 0.29 0.30 0.40 0.23 CeO₂ — — — — — — — — 1 — TiO₂ 0.03 0.03 0.030.03 0.5 0.5 0.5 1.6 0.03 0.03 Se(ppm) — — — — — 5 — 2 — — CoO(ppm) 98100 90 92 130 95 75 115 75 110 NiO(ppm) 300 300 50 100 300 — 500 — 500 —others CuO 0.22 YA 23.0 23.2 35.6 31.7 31.9 38.0 30.4 28.0 30.4 43.9 TG10.2 11.1 19.3 21.8 20.5 23.2 15.4 16.1 15.4 28.1 Tuv(ISO) 0.9 1.0 1.92.6 4.0 3.7 3.9 1.6 3.9 3.8 dominant 511 517 499 500 497 516 520 525 514492 wavelength Dw excitation purity Pe 7.3 6.6 7.4 6.6 7.5 4.1 8.3 9.88.3 9.6

[0085] TABLE 3 Example 22 23 24 25 26 27 28 29 SiO₂ 71 71 71 70 71 71 7171 Al₂O₃ 1.6 1.6 1.6 1.6 1.6 1.6 1.6 1.6 MgO 3.6 3.6 3.6 3.6 3.6 3.6 3.63.6 CaO 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 Na₂O 13.7 13.7 13.7 13.7 13.713.7 13.7 13.7 K₂O 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 B₂O₃ — — — — — — — —T-Fe₂O₃ 1.2 1.4 1.7 1.3 1.3 1.4 1.3 1.3 FeO/T-Fe₂O₃ 0.24 0.21 0.19 0.190.16 0.17 0.17 0.17 CeO₂ — — — 0.4 — — — — TiO₂ 0.03 0.03 0.03 0.03 0.500.03 0.03 0.03 Se(ppm) 3 — — — — — — — CoO(ppm) 110 130 100 120 300 80180 200 NiO(ppm) — 390 250 300 600 1900 1050 1000 YA 37.9 35.4 37.4 38.318.7 17.7 20.2 19.9 TG 21.2 28.4 24.6 29.8 25.2 21.8 21.1 23.2 Tuv(ISO)5.6 8.3 2.6 3.6 4.9 8.1 6.4 6.8 dominant 496 496 510 499 485 565 555 543wavelength Dw excitation purity Pe 5.9 6 4.7 5.3 16.1 22.9 9.7 5.9

[0086] TABLE 4 Example 30 31 32 33 34 35 SiO₂ 71 71 71 71 71 71 Al₂O₃1.6 1.6 1.6 1.6 1.6 1.6 MgO 3.6 3.6 3.6 3.6 3.6 3.6 CaO 7.7 7.7 7.7 7.77.7 7.7 Na₂O 13.7 13.7 13.7 13.7 13.7 13.7 K₂O 0.9 0.9 0.9 0.9 0.9 0.9B₂O₃ — — — — — — NiO(ppm) 330 330 330 1000 1000 900 Se(ppm) — — — — — —CoO(ppm) 120 125 120 190 180 190 TiO₂ 0.03 0.03 0.03 0.03 0.03 0.03t-Fe₂O₃ 1.3 1.3 1.3 1.3 1.3 1.3 FeO/T-Fe₂O 0.17 0.17 0.17 0.16 0.18 0.19before after before after before after before after before after beforeafter YA 38.8 37.4 37.2 35.9 37.8 36.3 20.2 17.8 20.2 17.7 20.4 18.1 TG31.4 31.2 30.5 30.5 30.3 29.9 21.7 21.2 20.3 19.7 19.8 19.3 L* 69.5068.38 68.37 67.25 68.79 67.59 52.54 49.63 52.63 49.54 53.01 50.27 a*−9.47 −8.31 −9.45 −8.32 −9.48 −8.36 −9.10 −6.27 −9.39 −6.25 −9.64 −6.76b* 0.78 0.59 0.14 0.01 −0.31 −0.34 6.72 3.77 6.19 2.96 3.39 0.69dominant 498.9 498.5 496.9 496.5 495.8 495.5 550.3 542.4 545.9 529.1514.9 499.5 wavelength Dw excitation 4.89 4.43 5.56 5.08 5.99 5.42 8.164.46 7.22 3.28 4.10 4.36 purity Pe Tuv(ISO) 6.73 5.06 6.35 4.73 6.995.14 5.86 4.18 6.78 4.84 6.56 4.74

[0087] TABLE 5 Comparative Example 1 2 3 4 SiO₂ 71 71 72 66 Al₂O₃ 1.61.6 1.7 3.1 MgO 3.6 3.6 4.1 3.1 CaO 8.4 8.4 7.8 7.9 Na₂O 13.1 13.1 13.517.8 K₂O 0.9 0.9 0.5 — B₂O₃ — — — — T-Fe₂O₃ 1.4 1.0 1.4 1.5 FeO/T-Fe₂O₂0.61 0.21 0.17 0.18 CeO₂ — — — — TiO₂ 0.03 0.03 0.1 — Se (ppm) — — 43 40CoO (ppm) 135 150 235 213 NiO 2200 300 — — thickness (mm) 4 4 5 3.9 YA12.6 40.0 17.1 15.6 TG 7.2 33.1 16.6 16.7 Tuv(ISO) 8.8 21.7 2.5 4.7dominant 587 483 530 576 wavelength Dw excitation purity Pe 18.0 20.53.9 8.9

[0088] TABLE 6 Example Comparative Example 36 Example 37 Example 5 SiO₂71 71 71 Al₂O₃ 1.6 1.6 1.6 MgO 3.6 3.6 3.6 CaO 7.7 7.7 7.7 NA₂O 13.713.7 13.7 K₂O 0.9 0.9 0.9 B₂O₃ — — — NiO (ppm) 770 770 770 Se (ppm) 0 12.1 CoO (ppm) 180 180 180 TiO₂ 0.03 0.03 0.03 t-Fe₂O₃ 1.26 1.26 1.26FeO/T-Fe₂O 0.216 0.214 0.209 YA 21.8 21.4 20.5 TG 18.6 18.6 18.5 L* 54.654.1 53.1 a* −8.8 −8.5 −7.8 b* −0.0 0.9 1.2 dominant 496.4 499.6 501.8wavelength Dw excitation 6.38 5.16 4.37 purity Pe

[0089] TABLE 7 Example 38 39 40 41 42 SiO2 70.5 70.5 70.5 70.5 70.5Al2O3 1.6 1.6 1.6 1.6 1.6 CaO 8.0 8.0 8.0 8.0 8.0 MgO 3.7 3.7 3.7 3.73.7 Na2O 13.9 13.9 13.9 13.9 13.9 K2O 0.8 0.8 0.8 0.8 0.8 T-Fe2O3 1.251.3 1.25 1.27 1.4 FeO/T-Fe2O3 0.23 0.18 0.23 0.23 0.21 TiO2 0.03 0.030.02 0.03 0.06 Se (ppm) <1 — — — — CoO (ppm) 110 120 170 130 130 NiO(ppm) 310 300 450 280 330 before after YA (%) 37.3 35.0 38.4 30.1 30.734.3 TG (%) 26.6 25.5 30.1 26.5 26.1 24.3 Tuv(iso) (%) 10.1 7.6 6.8 8.27.2 5.6 L* 67.57 66.66 85.56 62.82 68.03 66.33 a* −9.33 −8.65 −9.73−7.53 −10.63 −11.3 b* −1.3 −1.34 −0.33 −2.52 −3.12 −0.59 Dw(nm) 493.6493.3 495.7 490.9 491.2 495.3 Pe(%) 6.9 6.7 6.13 8.87 9.61 7.57

[0090] TABLE 8 {circle over (1)} {circle over (2)} {circle over (3)}{circle over (4)} {circle over (5)} SiO2 71.6 71.6 71.6 71 71 Al2O3 1.71.7 1.7 1.7 1.7 CaO 8.6 8.6 8.2 8.2 7.6 MgO 2.1 2.1 2.5 2.5 3.0 Na2O13.6 13.6 13.6 13.6 13.6 K2O 0.9 0.9 0.9 0.9 0.9 t-Fe2O3 1.3 1.3 1.251.25 1.3 FeO/t-Fe2O3 0.25 0.16 0.17 0.24 0.17 TiO2 0.03 0.03 0.03 0.030.7 CeO2 0 0 0 0.5 0 Se — — — — — CoO 0.01 0.012 0.008 0.012 0.017 NiO0.028 0.03 0.028 0.03 0.033 YA(%) 35.6 38.4 44.7 35.9 30.5 TG(%) 23.030.1 32.5 23.5 25.4 Tuv(ISO)(%) 8.0 6.8 7.5 3.8 3.7 L* 67.08 69.31 73.4867.72 63.14 a* −9.65 −9.73 −9.92 −12.17 −9.77 b* −1.42 −0.33 3.47 −0.99−1.77 DW(nm) 495 496 515 495 493 Pe(%) 6.8 6.1 3.2 8.4 8.2

What is claimed is:
 1. An ultraviolet/infrared absorbent lowtransmittance glass consisting of base glass comprising: 65 to 80 wt. %SiO₂; 0 to 5 wt. % Al₂O₃; greater than 2.1 to less than or equal to 10wt. % MgO; 5 to 15 wt. % CaO wherein a total amount of MgO and CaO is 7to 15 wt. %; 10 to 18 wt. % Na₂O; 0 to 5 wt. % K₂O wherein a totalamount of Na₂O and K₂O is 10 to 20 wt. %; and 0 to 5 wt. % B₂O₃, andcolorants comprising: 1.25 to 2.2 wt. % total iron oxide (T-Fe₂O₃)expressed as Fe₂O₃; 0.001 to 0.018 wt. % CoO; 0 to 0.0004 wt. % Se; and0.028 to 0.2 wt. % NiO, wherein said glass has a turquoise blue or deepgreen color.
 2. An ultraviolet/infrared absorbent low transmittanceglass as claimed in claim 1, wherein T-Fe₂O₃ is equal to or greater than1.25 wt. % and less than 1.8 wt. %.
 3. An ultraviolet/infrared absorbentlow transmittance glass as claimed in claim 1, wherein T-Fe₂O₃ isbetween 1.8 wt. % and 2.2 wt. %.
 4. An ultraviolet/infrared absorbentlow transmittance glass as claimed in claim 1, wherein Se is less than0.0002 wt. %.
 5. An ultraviolet/infrared absorbent low transmittanceglass as claimed in claim 1, wherein Se is less than 0.0001 wt. %.
 6. Anultraviolet/infrared absorbent low transmittance glass as claimed inclaim 1, wherein NiO is equal to or greater than 0.028 wt. % and lessthan 0.05 wt. %.
 7. An ultraviolet/infrared absorbent low transmittanceglass as claimed in claim 1, wherein NiO is between 0.05 wt. % to 0.2wt. %.
 8. An ultraviolet/infrared absorbent low transmittance glass asclaimed in claim 1, wherein said colorant further comprises CeO₂ in anamount of no greater than 2.0 wt. % and/or TiO₂ in an amount of nogreater than 2.0 wt. %.
 9. An ultraviolet/infrared absorbent lowtransmittance glass as claimed in claim 1, wherein the amount of FeOcalculated as T-Fe₂O₃ is in the range from 15 to 40% of T-Fe₂O₃.
 10. Anultraviolet/infrared absorbent low transmittance glass as claimed inclaim 1, wherein the glass with a thickness of 4 mm has a total solarenergy transmittance (TG) smaller than a visible light transmittance(YA) by the C.I.E. illuminant A, and YA is in a range from 23% to 50%and TG is in a range from 7% to 35%.
 11. An ultraviolet/infraredabsorbent low transmittance glass as claimed in claim 10, wherein YA isbetween 25% and 40% and TG is between 20% to 35%.
 12. Anultraviolet/infrared absorbent low transmittance glass as claimed inclaim 10, wherein the glass has a color defined by the following CIELABcoordinates −9<a*<−6 and −3<b*<3.
 13. An ultraviolet/infrared absorbentlow transmittance glass as claimed in claim 1, wherein said glass has anultraviolet transmittance of no greater than 6%.
 14. Anultraviolet/infrared absorbent low transmittance glass as claimed inclaim 1, wherein the glass has a dominant wavelength in a range of 480to 525 nanometers when a measurement is made based on a glass thicknessof 4 mm using illuminant C.
 15. An ultraviolet/infrared absorbent lowtransmittance glass as claimed in claim 1, wherein the glass has anexcitation purity less than 11% when a measurement is made based on aglass thickness of 4 mm using illuminant C.
 16. An ultraviolet/infraredabsorbent low transmittance glass as claimed in claim 1, wherein NiO isincluded in the glass such that the glass has the turquoise blue or deepgreen color by reinforcement of air blast cooling.
 17. Anultraviolet/infrared absorbent low transmittance glass consisting ofbase glass comprising: 65 to 80 wt. % SiO₂; 0 to 5 wt. % Al₂O₃; greaterthan 2.1 to less than or equal to 10 wt. % MgO; 5 to 15 wt. % CaOwherein a total amount of MgO and CaO is 7 to 15 wt. %; 10 to 18 wt. %Na₂O; 0 to 5 wt. % K₂O wherein a total amount of Na₂O and K₂O is 10 to20 wt. %; and 0 to 5 wt. % B₂O₃, and colorants without Se comprising:1.25 to 2.2 wt. % total iron oxide (T-Fe₂O₃) expressed as Fe₂O₃; 0.001to 0.018 wt. % CoO; and 0.028 to 0.2 wt. % NiO, wherein said glass has aturquoise blue or deep green color.
 18. An ultraviolet/infraredabsorbent low transmittance glass as claimed in claim 17, wherein NiO isincluded in the glass such that the glass has the turquoise blue or deepgreen color by the reinforcement of air blast cooling.
 19. Anultraviolet/infrared absorbent low transmittance glass as claimed inclaim 1, wherein MgO is more than 3.0 wt %.
 20. An ultraviolet/infraredabsorbent low transmittance glass as claimed in claim 17, wherein MgO ismore than 3.0 wt %.